c896VAG LTE ipv6 internet connection

[Jens Kuropka]

Hello there,

I´ve got a c896VAG LTE router and I can´t get the internet connection ipv6 up and running. As far as I´m concerned there seems to be no link from interface Vlan over the ipv6 dhcp pool to interface cellular. I´m able to ping clients from one to another and also from the routers CLI, so the ipv6 intranet seems to work fine. Also the Gigabitethernet interfaces are L2 so I´ll have to use some other L3 interface for configuration. I´ve been looking all over for information but couldn´t find anything so far.

Attached you´ll find the running-config.

Any help would be much appreciated.

[Rich R]

1. Does the cellular provider support IPv6 (most do but make sure the access point you're using does)?

2. Check the cellular IPv6 is working - can you ping from the cellular interface to internet - for example your DNS IP and sites like www.google.com?

[Jens Kuropka]

Hi Rich,

many thanks for your reply.

I do have IPV6 connectivity from my provider. I am also able to ping IPV6 addresses from the routers CLI. Attached you´ll find my Cellular profile. The problem seems that I have no connection between IPV6 DHCP pool and interface Vlan or from IPV6 DHCP POOL to the Cellular interface. Most configuration examples I´ve found so fare are with layer 3 (G)ethernet interfaces but the Gigabitethernet interfaces on the c896VAG are all Layer 2. That´s why I have to use Vlan interfaces instead.

Best Regards

[Harold Ritter]

Hi @Jens Kuropka ,

The reason you can't reach the IPv6 Internet from the VLAN side is that you configured a unique local address (ULA) prefix on that interface. These addresses are not routable on the IPv6 Internet, so it will not work unless you use NAT66.

The recommend approach would be to get additional IPv6 addresses from the service provider that you could use on the VLAN interface. You can use DHCPv6 prefix delegation to do that if you service provider supports it.

The prefix delegation configuration would look something like this:

interface Cellular0

 ipv6 dhcp client pd PD-prefix

interface Vlan36

 ipv6 address PD-prefix ::0:0:0:1/64

Regards,

[Jens Kuropka]

Hi Harold,

many thanks for your reply.

I´ve added your recommended lines to the configuration. In case my provider would supply additional IPv6 addresses how will I find them, is there a show command?

Best Regards,

Jens Kuropka

[Harold Ritter]

Hi @Jens Kuropka ,

You can use the following commands to get more information.

"show ipv6 general-prefix"

"show ipv6 dhcp interface Cellular 0"

Regards,

[Jens Kuropka]

Hi Harold,

many thanks again for your reply. As far as I´ve found out I´ve received only 1 ipv6 address prefix from my ISP, which is the same as for the connection of cellular interface. Using it on Vlan36 shows an error because addresses are overlapping. 

Regards

[Harold Ritter]

Hi @Jens Kuropka ,

Can you provide the output for the "show ipv6 dhcp interface Cellular 0".

Regards,

[Jens Kuropka]

Hi Harold,

attached is the output. Also attached "running-conf". As prefix I´ve tried to use one from the ISP which was in use before. But I guess if it is not assigned by the ISP it wont work.

Regards,  

[Harold Ritter]

Hi @Jens Kuropka ,

You are not receiving anything via DHCPv6 from your service provider. I recommend you talk to them to find out what is possible.

Regards,

[Jens Kuropka]

...many thanks.

[Harold Ritter]

You are very welcome and thanks for the feedback @Jens Kuropka 

[Harold Ritter]

By the way @Jens Kuropka , please keep us posted on the feedback you get from the SP

[Jens Kuropka]

...well, I´ve swapped my sim card to a mobile phone. Using the mobile as a hot spot provides IPV6 internet connectivity on clients. I also found out that the ISP provides only one IPV6 address which is used by the router.

PDP IPV6 address = 2A02:3033:404:965A:C881:CFFF:FE65:9F08/64 Scope: Global

Show command "sh ipv6 int cell 0 prefix" brings the following output.

PD default [LA] Valid lifetime 2592000, preferred lifetime 604800

AD 2A02:3033:404:965A::/64 [LA] Valid lifetime 2592000, preferred lifetime 604800

Is this ipv6 prefix in any way routable to clients?

Best Regards

[Harold Ritter · Accepted solution]

Hi @Jens Kuropka ,

> Using the mobile as a hot spot provides IPV6 internet connectivity on clients.

This is because the mobile and the router support different approaches.

The mobile does it in either one of these two ways, not supported in IOS.

1. Prefix sharing between the WAN interface and the LAN interface (RFC7278)

https://datatracker.ietf.org/doc/html/rfc7278

2. Using a ULA prefix on the LAN interface and performing NAT66 to nat the traffic to the IPv6 address obtain from the 3GPP network.

IOS on the other hand supports RFC7066, which uses DHCPv6 prefix delation.

https://datatracker.ietf.org/doc/html/rfc7066

> Is this ipv6 prefix in any way routable to clients?

This is the way proposed by RFC7278, which is not supported in IOS.

Regards,